Photothermal Deoxygenation of Graphite Oxide with Laser Excitation in Solution and Graphene-Aided Increase in Water Temperature

Materials Science-Poland

Zhu

2015

135

Graphene has achieved a great amount of popularity and interest from the science world because of its extraordinary physical, mechanical and thermal properties. Graphene is an allotrope of carbon, having one-atom-thick planar sheets of sp 2 bonded carbon atoms densely packed in a honeycomb crystal lattice. Many methods to synthesize graphene have been developed over a short period and we believe it is necessary to create a list of the most notable approaches. This article focuses on the methods to synthesize graphene in an attempt to summarize and document advancements in the synthesis of graphene research and future prospects.

Section: Radiation Based Methodsmentioning

confidence: 99%

Graphene synthesis: a Review

Shams

Materials Science-Poland

Zhu

2015

135

“…[106][107][108][109][110][111][112][113] Because of the high energy per unit pulse of the light, the bonds between the graphene sheet and the oxygen functionalities in GO can be destroyed to produce RGO with relatively less impurity. Moreover, this method can be exploited for nanopatterning and for large-scale production of reduced graphene oxide.…”

Section: Photoreductionmentioning

confidence: 99%

“…Moreover, this method can be exploited for nanopatterning and for large-scale production of reduced graphene oxide. Abdelsayed et al [111] employed a facile laser reduction method for preparing graphene from GO, and such effects of laser irradiation were associated with thermal effects. With the increasing of laser irradiation time, the temperature of the GO solution increased and the yellow golden color of the GO solution changed gradually to brown and finally to black, which indicated the deoxygenation of GO.…”

Section: Photoreductionmentioning

confidence: 99%

Recent Advances in Effective Reduction of Graphene Oxide for Highly Improved Performance Toward Electrochemical Energy Storage

Li²,

Energy & Environ Materials

et al. 2018

138

The demand for high‐quality graphene from various applications promotes the exploration of various synthesis methods such as chemical vapor deposition, chemical reduction of graphite oxide, liquid‐phase exfoliation, and electrochemical exfoliation. Among those, chemical treatments for the production of reduced graphene oxide (RGO) dictate the current technologies for mass production of graphene powder. However, such conventional chemical reduction methods are rather ineffective in removing oxygen‐containing functional groups from graphene oxide (GO), with resultant RGO products containing high level of structural defects. This leads to significantly damaged crystallinity and drastically lowered electric and thermal conductivity, which is probably the main bottleneck to limit the performance of RGO‐based materials. Great efforts such as thermal reduction, microwave‐irradiation reduction, or other novel reduction methods (e.g., photoreduction) have been developed to repair defects in RGO materials. This perspective review is to outline the latest advances toward effective reduction of GO for significantly enhanced properties. We demonstrate that effectively repaired RGO with large specific surface area and highly improved crystallinity is key to highly improved electric and thermal conductivity, thus leading to significantly enhanced properties essential for chemical energy storage devices.

“…GO can be successively reduced to graphene by the partial restoration of the sp 2 -hybridization by thermal [127], chemical [128], electrochemical [129], photothermal [130], Catalysts 2017, 7, 305 6 of 34 photocatalytic [69,131], sonochemical [132,133], and microwave reduction methods [134]. The high number of oxygen-containing groups of the obtained GO product permits the interaction with the cations, providing important reactive molecules for the nucleation and growth of nanoparticles and therefore the formation of various graphene-based composites.…”

Section: Introductionmentioning

confidence: 99%

Recent Advances in Graphene Based TiO2 Nanocomposites (GTiO2Ns) for Photocatalytic Degradation of Synthetic Dyes

et al. 2017

Synthetic dyes are widely used in textile, paper, food, cosmetic, and pharmaceutical industries. During industrial processes, some of these dyes are released into the wastewater and their successive release into rivers and lakes produces serious environmental problems. TiO 2 is one of the most widely studied and used photocatalysts for environmental remediation. However, it is mainly active under UV-light irradiation due to its band gap of 3.2 eV, while it shows low efficiency under the visible light spectrum. Regarding the exploration of TiO 2 activation in the visible light region of the total solar spectrum, the incorporation of carbon nanomaterials, such as graphene, in order to form carbon-TiO 2 composites is a promising area. Graphene, in fact, has a large surface area which makes it a good adsorbent for organic pollutants removal through the combination of electrostatic attraction and π-π interaction. Furthermore, it has a high electron mobility and therefore it reduces the electron-hole pair recombination, improving the photocatalytic activity of the semiconductor. In recent years, there was an increasing interest in the preparation of graphene-based TiO 2 photocatalysts. The present short review describes the recent advances in TiO 2 photocatalyst coupling with graphene materials with the aim of extending the light absorption of TiO 2 from UV wavelengths into the visible region, focusing on recent progress in the design and applications in the photocatalytic degradation of synthetic dyes.